Spring rod for underreamers



March 30,1926. 1,578,482

; F. SWAN 7 SPRING ROD FOR UNDERREAMERS Filed Oct. 20, 192

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Fig.1. r gmemu Fred Swan.

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Patented Mar. 30, 1926.' i l UNITED STATES PATENT oFFicE.

man swan, or manm'rm, OHIO.

srnme ROD non UNDERREAMERS.

Application filed October 20, 1924. Serial No. 744,599.

To all whom it may concern: held until as the tool body is drawn upward 60 Be it known that I, FRED SWAN, a citizen the downwardly tapering ways. cause the of the United States, residing at Marietta, cutters to move radially inward so that they in the county of Washington and State of may pass into the casing. As the tool body Ohio, have invented certain new and useful is drawn into the lower end of the casing the Improvements in Spring Rods for Undertrips enter the casing before the cutters and, reamers, of which the following is a specifibeing forced inward, will prevent the procation, reference being had to the accomje-ctions on the spring rod from passing palnlying drawing, forming a part thereof. downward past them, and if these projec- 10 y invention relates to improvements in tions are fixedon the spring rod, will prespring rods of-under-reamers such as the vent such relative movement of the tool Swan under-reamer shown in U. S. patents body and cutters as is required to bring to John C. Swan, Nos. 683,352 dated Sept. the cutters down to the lower ends of the 24, 1901, and 979,106 dated Dec. 20, 1910. inclined ways. While if the projections on 15 In Swan under-reamers as well as in other the spring rod which are. engaged by the under-reamers and in a number of other extrips in introducing the tool into casing are pansibletools used in well drilling which fixed, and being above the trips. when the are adapted to be introduced through castrips are moved inward and will thus preing, and to be expanded below casing to en-- vent the cutters from being drawn as closely large a hole drilled below casing or to drill together as they are drawn for introduction below casing a hole of greater diameter than into the upper end of the casin there is 7 the interior of the casing, the cutters are usually suflicient margin of difference beslidable on inclined ways into and out of tween the distance between the outer edges expanded position, these inclined ways, norof the cutters when they are as near the 25 mally, as in the Swan under-reamer, being lower ends of the ways as is possible while so arranged that as the cutters slide upward the projections on the spring rod are still on the inclined ways they are forced radially above the trips, it sometimes happens that outward and as they are drawn downward the cutters are overdressed, that is, in dresson the tool body they move inward so that ing them their outer edges. are spread too 30 when at their lowest position their outer much. When the cutters are thus 'overedges are within a circle not greater in dressed the distance between their outer diameter than is theinterior of the casing. edges may be such that when they are as In the construction to which my present near the lower ends of the inclined ways improvement is applied the cutters are conas the spring rod will permit, they will not 35 nected to a spring rod which is movable enter the casing but will hold the tool locked longitudinally of the tool body and is acted against withdrawal. upon by a spring carried within the tool My present invention is intended to obvibody to draw the cutters upward into ex ate this difficulty by so constructing the panded position. To hold the cutters in 001- spring rod that the portions carried by it lapsed position for introducingthe tool into which are engaged by the trips will permit a and' lowering it through the casing the a limited downward movement of the spring spring rod is locked against the tendency of rod, and with this object in view my inventhe spring to draw it upward by trips which tion consists in the construction and combiengage the spring rod and are held in nation of elements hereinafter described and engagement therewith by the walls of the claimed. 1 Y Y In drawing out an expanding tool of this Figure 1 is a longitudinal view of a Swan character the cutters as they are drawn upunder-reamer in posltion to operate below ward into the lower end of the casing are casing.

casing. Referring to the drawings:

Fig. 2 is a similar view showing a, Swan under-reamer entering the lower end of casmg.

Fig. 3 is a side view of ai spring rod provided with my improvement.

Fig. 1 is a vertical sectional view on line 4-4 of Fig. 3.

Fig. 5 is a detailview of the slide shown in Figs. 3 and 4.

In the drawings 1 indicates the tool body having at its lower end downwardly tapering inclined ways 2 in which are guided the cutters 3. Cross bar 4 carried in a slot at the lower end of spring rod 5 connects these cutters with the spring rod which extends upward into a central chamber 6 in which is ar-- ranged spring 7 which acts upon the spring rod to draw it upward and, through the spring rod, to draw the cutters upward on the tapering ways to come into contact with abutment 8. In the walls of the tool body are formed radial recesses-in which are received trips 9, the outer end portions of which are adapted to contact with the interior of the casing to hold the pins 10 against the spring rod and, by engaging above projections on the spring rod when it is drawn down against the face of the spring, act to hold the spring rod in this downward position and thus hold the cutters in collapsed position. The projections usually used on the spring rodare fixed.

In order to permit'downward movement of the spring rod beyond the point at which it will be held by engagement of the projections above the trips, as may be necessary to permit cutters which are dressed oversize to enter the casing, I form the'projections ll'with Which the pins 10 of the trips 9 engage, on a slide 12 which is movable in a slot 13, extending longitudinally through a preferably slightly flattened portion 14 of the spring rod. The slide 12 is so formed that when its lower end fits against the lower end of the slot 13 its upper end is'sufficiently away from the upper end ofthe slot to permit considerable movement. A coiled spring 15 between the upper end of the slide and the upper end of the slot tends to keep the slide with its lower end against the lower end of the slot but this spring may be omitted.

The slide 12 is preferably formed in one piece with the projections 11 and in order ,to placeit in position the sides of the slot 13 are preferably heated and spread, .the slide inserted and the sides forced back into position.

When the under-reamr is to be introduced into the top of the casing the cutters are drawn down into collapsed position and inserted into the casing. As the trips enter the casing they are forced and held inward with their pins 10 engagin the upper faces of the projections 11 holding the slide 12 trips and if these projections were fixed,

might so hold the spring rod against downward movement as to prevent the cutters, if dressed over size, from entering the lower end of the casing. By the movement of the spring rod permitted by the slide the difliculty is overcome and the upward pull of the tool body will so draw it through the cutters'that they will be so drawn inward as to permit them to enter the casing.

It will, of course, be understood that the invention is not limited to use with the Swan under-reamer or to any particular underreamer or expanding drilling tool, but is applicable to any form of tool in which the cutters'slideon inclined ways and are drawn into expanded position by a spring rod adapted to be locked against movement by trips.

Having thus'described my I claim is 1. In a well drilling tool, a body provided with tapering ways, cutters slidable in said ways into and out of expanded position, a spring for sliding the cutters upon the ways into expanded position, a spring rod connecting the cutters and the spring and means for engaging the spring rod to. hold the cutters in contracted position against the force of the spring comprising trips carried by the invention what tool body, and a slide carried by the spring rod provided with projections to be engaged by the trips, said slide being so mounted on the spring rod as to permit the spring rod to move relative to said projections against the force of the spring by which the spring rod is operated, and yielding means carried by the spring rod for resisting relative move ment of the slide and spring rod.

2. In a well drilling tool, a bod provided with tapering ways, cutters slidable in said ways into and out of expanded position, a spring for sliding the cutters upon the ways into expanded position, a spring rod connecting the cutters and the spring and means for engaging the spring .rod to hold the cutters in contracted position against the force of the spring comprising trips carried by the tool body, and a slide carried by the spring rod provided with projections to be engaged by the trips, said spring rod being provided with a longitudinal slot and said slide extending through and .being movable in said slot so as to permit the spring rod the force of the spring by which the spring rod is operated.

3. A spring rod for use in expansible drilling tools of the type in which the cutters are slidable on tapered ways into ex panded position by a spring and are held in contracted position against the force of the spring by trips, said spring rod being adapted to serve as the connecting means 10 between the cutters and the spring and'having a lon itudinal slot formed therein, a slide mova hle in said slot and carrying projections for engagement with the trips, and means arranged in said slot adapted to yieldingly hold the slide against one end 15 FRED SWAN. 

